This contract is to perform chronic tests of Manganese Sulfate and Triamterene using a dosed feed route of administration to F344 rats and B6C3F1 mice. 104-week chronic studies using 70 animals per group of both sexes of both species with two interim sacrifices at three dose levels plus controls will be conducted. These tests will determine the potential for carcinogenicity and systemic toxicity of these chemicals after a chronic exposure.